Change to read:
Identification—
A: Infrared Absorption 
197K
—
Test specimen—
Transfer a quantity of finely powdered Tablets, equivalent to about 90 mg of paroxetine, to a suitable flask, add 100 mL of 0.1 N hydrochloric acid, and stir for 1 hour. Transfer the mixture to a separatory funnel, and add
1.5 mL of ammonium hydroxide to make the solution alkaline.
USP29 Add 100 mL of ethyl ether to the funnel, and shake for 2 minutes. Transfer the organic layer into the necessary number of centrifuge tubes, and centrifuge for 10 minutes. Recombine the clarified extracts, add 1 drop of water and 0.5 mL of
USP29 hydrochloric acid, stir, and evaporate to dryness under a stream of nitrogen. Dry the residue in an oven at 90
for 1 hour.
B:
The retention time of the major peak in the chromatogram of the Assay preparation corresponds to that in the chromatogram of the Standard preparation, as obtained in the Assay.
C:
Place a quantity of finely powdered Tablets, equivalent to about 450 mg of paroxetine, in a stoppered flask. Add 100 mL of alcohol, and shake for 1 hour. Centrifuge about 20 mL of the mixture, and measure the
specific
USP29 rotation of the supernatant at 20
(see
Optical Rotation 781): the
specific
USP29 rotation is between –75
and –115
.
Dissolution 711—
Medium:
simulated gastric fluid without enzyme; 900 mL.
Apparatus 2:
60 rpm.
Time:
60 minutes.
Determine the amount of C19H20FNO3 dissolved by employing the following method.
Buffer solution and Mobile phase—
Prepare as directed in the Assay.
Standard stock solution—
Dissolve an accurately weighed quantity of
USP Paroxetine Hydrochloride RS in an amount of methanol not exceeding 5% of the volume of the final solution, and dilute with
Medium to obtain a solution having a known concentration of about 0.63 mg per mL.
Standard solution—
Quantitatively dilute the Standard stock solution with Medium to obtain a solution having a concentration estimated to correspond to that of the filtered solution under test.
Chromatographic system—
Proceed as directed in the Assay, except to chromatograph the Standard solution.
Procedure—
Separately inject equal volumes (about 20 µL) of a portion of the solution under test, previously passed through a suitable 0.45-µm membrane filter, and the Standard solution into the chromatograph, record the chromatograms, and measure the responses for the major peaks. Calculate the quantity of C19H20FNO3 dissolved based on the peak responses obtained from the solution under test and the Standard solution.
Tolerances—
Not less than 80% (Q) of the labeled amount of C19H20FNO3 is dissolved in 60 minutes.
Uniformity of dosage units 905:
meet the requirements.
PROCEDURE FOR CONTENT UNIFORMITY—
Buffer solution, Mobile phase, and Chromatographic system—
Proceed as directed in the Assay.
Standard solution—
Use the Standard preparation, prepared as directed in the Assay.
Test solution—
Place 1 Tablet in a suitable volumetric flask, and add a volume of a hydrochloric acid solution (7 in 1000), equivalent to about 25% of the flask volume. Allow the Tablet to disintegrate, dilute with methanol to volume, and mix to obtain a solution containing about 0.1 mg of paroxetine per mL. Centrifuge a portion of the solution.
Procedure—
Proceed as directed in the
Assay. Calculate the quantity, in mg, of C
19H
20FNO
3 in the Tablet taken by the formula:
VC(329.37/365.83)(rU / rS)
in which
V is the volume of the flask used;
rU and
rS are the peak responses obtained from the
Test solution and the
Standard solution, respectively; and the other terms are as defined therein.
Assay—
Buffer solution—
Prepare a mixture of water, phosphoric acid, and triethylamine (100:0.6:0.3).
Mobile phase—
Prepare a filtered and degassed mixture of
Buffer solution and acetonitrile (7:3). Make adjustments if necessary (see
System Suitability under
Chromatography 621).
Standard preparation—
Dissolve an accurately weighed quantity of
USP Paroxetine Hydrochloride RS in methanol, and dilute quantitatively, and stepwise if necessary, with methanol to obtain a solution having a known concentration of about 0.1 mg per mL.
Assay preparation—
Weigh and finely powder not fewer than 20 Tablets. Transfer an accurately weighed portion of the powder, equivalent to about 100 mg of paroxetine, to a 200-mL volumetric flask, dissolve in and dilute with methanol to volume, and mix. Centrifuge a portion of this solution for 6 minutes. Transfer 20 mL of the supernatant to a 100-mL volumetric flask, dilute with methanol to volume, and mix.
Chromatographic system (see Chromatography 621)—
The liquid chromatograph is equipped with a 295-nm detector and a 4.6-mm × 3.3-cm column that contains 3-µm packing L7. The flow rate is about 2.0 mL per minute. Chromatograph the
Standard preparation, and record the peak responses as directed for
Procedure: the column efficiency is not less than 750 theoretical plates; the tailing factor is not more than 4; and the relative standard deviation for replicate injections is not more than 2.0%.
Procedure—
Separately inject equal volumes (about 5 µL) of the
Standard preparation and the
Assay preparation into the chromatograph, record the chromatograms, and measure the responses for the major peaks. Calculate the quantity, in mg, of paroxetine (C
19H
20FNO
3) in the portion of Tablets taken by the formula:
1000C(329.37/365.83)(rU / rS)
in which
C is the concentration, in mg per mL, of
USP Paroxetine Hydrochloride RS in the
Standard preparation; 329.37 and 365.83 are the molecular weights for paroxetine and paroxetine hydrochloride, respectively; and
rU and
rS are the peak responses obtained from the
Assay preparation and the
Standard preparation, respectively.
